With the continuous advent of various electronic components newly developed, and additionally the requirements of maintenance, a notebook computer's user frequently needs to dismantle the top case of the notebook computer's main unit, so as to replace, repair or upgrade various important components, such as a CPU, a thermal module, a VGA card, a keyboard or a touch pad, etc.
For the consideration of structure and EMI (Electromagnetic Interference), the mechanism designs of conventional notebook computers all tightly combine the upper and lower cases of the main units, and also use screws for further fastening, so that the step of dismantling the upper and lower cases of the main unit is quite complicated and difficult. Generally, a common notebook computer can have a relatively good design of replacing a CPU by merely dismantling a keyboard. However, for replacing a thermal module, there is still lacking a design for effectively simplifying the step of replacing the thermal module. Particularly, when the thermal module is over-sized, users usually have to separate the top case of the notebook computer's main unit completely from the notebook computer's main unit, so as to smoothly replace a thermal module. The aforementioned shortcoming not only costs the users a lot of time and effort for maintaining the notebook computers, but also hinders the DIY (Do It Yourself) market from entering the field of notebook computer.
Hence, there is a need to develop a detachable and rotatable door cover assembly, thereby simplifying the steps of replacing a thermal module, thus saving a lot of manpower and material cost, further benefiting the DIY market to enter the field of notebook computer.